Field of the Invention
This invention pertains to automatic controls for the engine air circulation system through an automotive vehicle condenser, shutter, radiator and fan as commonly used in large trucks and tractor-trailer combinations.
Description of the Prior Art
It is common with large, heavy-duty trucks to provide an air conditioning unit for the cab of the truck with the refrigerant condensor being located in line with the radiator and fan and most commonly placed in front of the radiator and fan. It is also common practice to place louvers or shutters in the air circulation path to block circulation of air through the radiator. Fans are commonly automatically de-energized when not necessary for air circulation. Thus in the normal idling condition a truck engine runs cool such that the shutters will normally be closed and the fan will be de-energized.
As trucks have become more sophisticated with these various air circulation controls, problems have frequently been encountered where the controls conflict with one another or are inadequate to adequately adjust to the various conditions under which the vehicle is used so that one or more of the systems or controls is rendered inoperative and unable to perform its necessary function.